The present invention relates to machines for mounting a tire on an removing a tire from its wheel rim, and more particularly relates to machines able to adapt to all currently available types of tires and wheel rims, and to the optional accessories with which known machines can be provided.
Special tires are known which ensure that a vehicle is able to travel even under low pressure conditions, ie, when the tire inflation pressure is very low or close to zero, as happens in the case of a puncture. Such tires are known hereinafter simply as special tires.
These special tires comprise not only a external carcass but also a separate toroidal support ring made of elastomeric rubber, which is housed in an appropriate seat provided in the wheel rim well.
To enable the tire and the toroidal support ring to be mounted on the wheel rim, both the wheel rim and the tire are constructed with special profiles.
Specifically, the special tire has different diameters at its beads, with the result that the wheel rim is not symmetrical about a plane passing through its center. Furthermore the wheel rim includes seats for receiving the different-diameter beads. In addition the beads of the special tire have a much smaller thickness than those of known tires and tires are less resistant to mechanical stresses and more fragile than known beads.
These new special tires are described in French patent applications FR 92/15061 and FR 93/14702.
To remove or mount these special tires from the wheel rim or to the wheel rim, a procedure has to be used which cannot be followed by removal machines of the traditional type, because of the asymmetry of the tire beads and the need to insert the toroidal ring on the wheel rim.
Attempts to construct specific tire removal machines for this type of tire have been unsuccessful both for reasons of cost and because of the particular operating methods required.